Apple unveils iPhone X, loses home button

Apple has paid homage to its late co-founder Steve Jobs for the 10-year anniversary of the iPhone unveiling its latest - and almost certainly most expensive - new version of the device, the iPhone X.

On Tuesday chief executive Tim Cook called it "the biggest leap forward" since the first iPhone. ("X" is pronounced 10, not the letter X.)

It loses the home button, which revolutionised smartphones when it launched; offers an edge-to-edge screen; and will use facial recognition to unlock the phone.

Apple also unveiled a new iPhone 8 and a larger 8 Plus with upgrades to cameras, displays and speakers.

Those phones, Apple said, will shoot pictures with better colours and less distortion, particularly in low-light settings. The display will adapt to ambient lighting, similar to a feature in some iPad Pro models. Speakers will be louder and offer deeper bass.

Both iPhone 8 versions will allow wireless charging, a feature thought to be limited to the anniversary phone. Many Android phones, including Samsung's, already have this.

This is the first product event for Apple at its new spaceship-like headquarters in Cupertino, California.

The iPhone X, which comes a decade after Jobs unveiled the first version, could also cost $US1,000 ($A1,247), twice what the original iPhone did. It would set a new price threshold for any smartphone intended to appeal to a mass market.

Apple's latest Watch has built-in cellular service. The number on your phone will be the same as your iPhone. The Series 3 model will also have Apple Music available through cellular service.

Apple is also adding more fitness features to the Watch, and says it is now the most used heart rate monitor in the world. Now, Apple Watch will notify users when it detects an elevated heart rate when they don't appear to be active. It'll also detect abnormal heart rhythms.

The Series 3 will start at $US399. One without cellular goes for $US329, down from $US369 for the comparable model now. The original Series 1, without GPS, sells for $US249, down from $US269. The new watch comes out September 22.